Hydraulic press



J-, El@ WH, J. MAYNAWD HYDRAULI C PRES S Filed Dec. 9, 1937 2Sheets-Sheet l .A Y( INVENTOR. 5% James May/10rd ATTORNEY.

Filed Dec. 9, 1937 2v Sheets-Sheet 2 INVENTOR. Jaw/7765 May/70rdATTORNEY.

Patented Jan. 16, 1940 PATENT OFFICE' 2,191,385 irrnminuc` rREss .lamesMaynard, Los Angeles, Calif., assigner to Frank R. Galbreath, LosAngeles, Calif.

Application December 9, 1937, Serial No. 178,964

" aolaims. (otros- 37) l Myinvention relates to hydraulic presses. Animportant object of the invention is to provide in a `hydraulic pressdriven by a constant speed motor, mechanism for progressively decreasingthe speed of the pressing jaws indirect proportion with the increase ofpressure required.

Other objects are to provide means in a hydraulic press whereby theprime mover, though continuously operating at a constant speed, may

maintain pressure on the pressing jaws substantially constant, maydecrease the pressure slowly or rapidly, or may increase the pressure ata speed in inverse proportion to the increase in the pressurerequirement at the work station.

A further object in a hydraulic press is to provide mechanism wherebythe pump piston or pistons always draw in their maximum amount of liquidon the suction stroke, irrespective of the power requirement, and theprovision of means to utilize varying amounts of the pressure liquid onthe power stroke of the pistons, depending upon the pressurerequirements of the press.

The invention also comprises novel details of construction and novelcombinations and `arrangements of parts, which will more fully appear inthe course of the following description;

In the drawings, like reference characters designate similar parts inthe several views.

Figure l is a plan View, partly broken away,

showing an embodiment of my invention.

Figure 2 is a side elevation of said embodiment, showing `in section atank comprised in the invention.

Figure 3 is a broken, enlarged View of the principal actuatingmechanism, as shown in Figure 2.

Figure 4 is an enlarged vertical section taken on the linel 4-4 of`Figure 1, looking in the direction ofthe arrows; i

Figure 5 is a section taken on the line 5--5, looking in the directionof the arrows. q

Figure 6 "is an enlarged section `taken on the line 1L-,Ei of Figure 3.

Figure l is a broken section taken on the line l--l of Figure 1.

Referring more in detail to the drawings, the refer-ence numeral 5designates generally a frame having arelatively fixed jaw 'l andrelatively movable pressing jaw 8. l The movable -jaw 8 is slidable'on atrack 9 on the frame E.

A helical ,springlll abuts, and thereby resists pressing movements of,`the movable jaw B. A rod l2 in the springprevehtsthe latter frombuckling. p

To actuate the movable jaw 8, a piston i3 is provided in a cylinder I4.A piston rod l5 connects the piston with the movable jaw 8.

The prime mover of the mechanism is an electric motor lli having avertical drive Shaft l1 mounted in a bearing block I8. The lower portionof the shaft I'l is provided with crank arms I9.

A double faced, rotary cam 2| is mounted `on the shaft ll between abearing 25 and the motor I6. One face of the cam faces upward and theother downward. The cam faces are reversed With respect to each other,but otherwise similar. Each face comprises a depressed plane 22, araised plane 23 and an incline 24 leading from one 1 plane to the other.

Riding on the upper cam face is a roller 25, while a roller 25 rides onthe lower cam face. The rollers 25 and 26 are respectively carried bycranks 2l and 28. The shape of these .cranks is perhaps best shown inconnection with crank 21 2Q in Figure 5. Cranks `2l? and 28 arerespectively pinned at one end of each of the rods 29 and 39. Sleeves 3land 32 are respectively pinned to the opposite ends of the rods 29 and3U. The sleeves 3l and 32 have squared female openings 25 33. Thesleeves 3l and 32 are thereby slidable on squared ends ci bars 34 and 35respectively. The bars 34 and 35 are otherwise cylindrical, whereby theymay be mounted in a double bearing 35 for rotation. 3U

,Crank arms 3'! and 3B are on projecting ends of the bars 34 and 35respectively. Tappet rods 39 and 4U connect with fingers 4l and 42through the intermediary of cranks 43 and 44 on the ends of spindles 45and 46 respectively-` The fingers 35 4l and 42 are mounted on a valvehousing 4lby means of the spindles 45 and 46. The lingers 4i and 42respectively maintain intake valves 48 and 49 away from their seats inthe valve housing 41. Light springs 5U are 'disposed behind the intake4Q valves.` `,A common intake 5l in the housing 4l provides an inlet forliquid.

The housing 4l has bores 52 and 53 alined with `the bores of twincylinders 54 and 55. Pistons 55 and 5l' reciprocate in the cylinders 54and 55 45 respectively. l Connecting rods 58 and 59 connect the pistons55 and 5l with the crank arms I9 of the crank shaft I1.

The discharge ends of the bores 52 and 53, within `the housing 4l, areconnected with pas- 50 sages 63 and 6l respectively. Check valves 62 and53 prevent` retrograde movement of liquid back into the passages G0 and6| from a main or common passage 54. Light springs 65 are arrangedbenindthe check valves 62, 63. 55

Passage 64 has two branches 56 and 61. Fluid -discharging through theoutlet 68 of the branch 66 empties into a bore 69 leading to theinterior of the press cylinder I4.

The mechanism is largely submerged in a body of oil 10 in a tank 1I. Byreason of the connections hereinbefore explained, liquid is being pumpedinto the passage 6:. whenever the motor i5 is operating. When it isdesired not to actuate the pressing jaw, the liquid in the passage @diis ley-passed back into the body of oil 1li, by means of the branch 61.

A valve 12 controls the discharge from th branch conduit t1. Areplaceable seat 13 is pro.- vided for the valve 12.

charge spout 14 back into thebody of oil.

The valve 12 is controlled by-a hand wheel 15, which operates bevelgears 16, 11'. The bevel gear 16 is keyed to a tubular shank 18 of thevalve 12. The shank 13 is threaded to engage interior threads 19 in abushing 8H; Thus by rotation of the bevel gears the shank 18 is raisedand lowered and the valve 12 is opened and closed.

The valve 12 is a combined control valve and relief valve. The valve 12is tubular. A plunger 8l controls the passage through the valve 12. Acollar 82 on the plunger 8i is engaged by a coiled spring $3 in thetubular shank 18. A threaded head 8A is disposed to compress the spring83. to vary the pressure necessary to open the relief valve 8l. A stem85 on the head 34 may be rotated by a hand wheel or suitable tool. Anoutlet 86 through the wall of the tubular valve 12 permits discharge ofexcess pressure liquid when the relief valve is opened.

As the pressure builds up in the cylinder I4, a portion of it escapesinto a passage 81. An upwardly directed conduit 88 in a casting Bil,connects `the passage 81 with a relatively small cylinder 9U for aplunger 9|. The plunger Sil carries a floating carrier 92. An upwardlyprojecting yoke 93 spans the squared portion of the bar 34. Collars Si!are mounted on the bar 34 at either side of the yoke 93. to communicatemovement of the noating carrier 92 to the cam roller 25. through theintermediary of the sleeve 3l, rod 2S and crank 21'. o

A downwardly projecting yoke B5 spans the squaredportion of the bar 35.Collars 9b are mounted on the bar 35 at either side of the yoke 95. tocommunicate movement of the floating carrier 92 to cam rollery 26.through the intermediary of the sleeve 32. the'rod and the crankLaterally the carrier 92 yhas bifurcatedy lugs 91 9H. the bifurcationsof which receive and slide on plates 99 and mit which plates are bolted.to side members il!! and M52 on the .A coiled spring M3 opposes movementof the carrier 92 to the right in Figure 3. The spring .53 is containedin telesconing tubes lil!! and M5. A head. HiB on the tube HB5 has athreaded connection |01 with a stationary abutment i338 also on. theframe of theanparatus. By means of this threaded connection, the tensionon the spring HW may be adjusted.

Strengthening ribs for the pressing jaws are provided as suggested atH39. Furthermore. between the motor i6 and the shaft I1, I preferablyarrange epieyclic gearing to get a fly wheel effect. Since the detailsof such gearing are not per se part of the present invention, it isbelieved that illustration and detailed description of same are VWhenthe` valve 1?.`A is open, liquld flows from the oonduitdill to the dis`unnecessary. The housing for such gearing is shown at H0.

The operation of my hereinbefore vdescribed hydraulic press is asfollows:

After starting the motor i6, the operation of the movable jaw 8 iscontrolled manually by means of the hand wheel 15. It is of courseunderstood that the relief valve 8l is adjusted to blow off at a desiredpressure. The hand wheel 'it controls the valve 12. The latter valvedetermines whether all the flow, or which portion of the flow, from thecylinders 54, 55 returns to the body of liquid 'it without actuating thepress.

Assume rst that the valve 12 is closed. Of course, the pistons 56, 51are being driven by means of the crank shaft i1. On the power strokeofthe pistons 56, 51, the flow from the cylinders 54, 55 is dischargedinto passages El), Gl, and since the check Valves 48, 139 are closed onthe power strokes, the liquid pumped into the passages ii, Si therebydischarges through the passages 62, G6 and through outlet @8 to the boreleading into the press cylinder Hl.

The pressure in the cylinder ifi actuates the piston it, moving themovable jaw 8 toward the ixed jaw 1.

On the suction strokes of the pistons, the check valves 55, lill aremoved from their seats. permitting measured quantities of oil to bedrawn from the reservoir'll through the inlet 5i and into the cylinders55. It is of course understood the pistons 56, 51 are connected withopposite throws of the crank shaft, so that one is discharging while theother is drawing in a new supply.

It is also to be understood that one cylinder or more than twocylinders, may also be ernplcyed, since the principle would beunchanged.

Rotation of the shaft El also effects rotation of the cam 2l. As thepressure builds up in the main cylinder ill, some pressure escapesthrough the passage il, through conduit 88 and into cylinder @il behindthe plunger Si. As the pressure in the small cylinder @il builds up, therollers 25 and 2li are fed laterally acrossthe rotating cam from thecircumference toward the center, by means of the floating carrier 22,rods 2S, and 3G and the cranks 21 and 28.

The cam rotates in the direction of the arrow in Figure 5. This figureshows the position of the roller 25 at the start of the intake stroke ofthe lower piston 51. After the valve it has been opened by the beginningof the suction stroke of the piston 51 (or simultaneously with suchopening of the valve 38), the incline 2d of the upper face of the camraises the roller 25 from the depressed plane 22 to the raised planethus rocking the crank 2l. This rocking motion rotates the sleeve 3l andthe squared bar 3A, by means of their angular it. Rotation of the bar3P', eiiects rocking of the arm 31. which rocks the nger 4l, through theintermediary of the tappet rod 39. The finger il then bears against thevalve 48, maintaining said valve in an open position..

When the edge 23a. of the raised plane of the cam reaches the roller 25,the roller drops down tothe depressed plane 22 of the cam face, thusrocking the crank 21 back to its original position and allowing thevalve i8 to be closed, by a reversal of the movement of the operatingparts between the roller 25 and the valve 48, described in the previousparagraph.

It will be noted that due to the snail shape of the drop-off edge 23a,as the roller 25 is moved 2,187,3854 closer toward the center oi thecam, the valve `the liquid in the cylinders 5d and 55 is pumped backinto the reservoir 'H past the valve 4&3, which is being held open bythe linger i I.

The operation of the valve fill, its actuating roller 2li and theintermediary mechanism is similar to that just *described in connectionwith valve Mi, roller 2li and associated mechanism, except thattheyoperate at diametrically opposite points in the cycle of operationof the machine.

The valves {i2} 53 act as check valves to prevent retrograde movement ofliquid in the passage dfi.

Thus it will be noted that preferably (though not essentially) the`fingers di, l2 are not employed to open the valves lid, limbut merelyto maintain the valves open, thus permitting a lighter construction.

Moreover, by holding said valves open pro gressively longer periods asthe pressure requirement at the work station increases, the speed ofmovement of the movable jaw is automatically and proportionately reducedeven though the `motor it is operating at a constant speed. By

using relatively smaller portions of the discharge of the pumps,` as thepressure requirement increases, the horsepower of the motor does not`have to be increased. By propelling the movable i is that the cylinders52, 53 are lled on eachsuction stroke, irrespectiveof the pressureencountered. This mode of operation` makes measurement ofthe amountdischarged more accurate, by

eliminating air pockets in the liquid.

Still another advantage of the present invention is that pressure of thepressure jaws may be `maintained constant by opening the valve 'l2 justsuiiicient to balance the amount being pumped into the passage 6d by thepistons.` The additional amount Vthat the valve 12 is then opened willdetermine the speed of recession of the jaw i t, or partially closingthe valve 'l2 will cause the jaw t to move forward at a reduced rate ofspeed. Thus the speed of applying pressure, the speed vof reducing thepressure, orA the maintaining of a l certain pressure may be regulatedby the hand wheel 'i5 `operating the valve 12.

` As increasing pressures are applied to compress the spring lll, thetension of the spring .thus increases, which tends to balance thepressure against the movable jaw at the Working point. The spring l #lliof course tends to move the rollers titi, if toward the periphery of thecam. The springs iid, iid tend to seat the ball `valves in the housing41.

While I have illustrated and described what I now regard as thepreferred embodiment of my invention, the construction is, of course,subject to modiiications without departing from the spirit of myinvention. I, therefore, do not wish to restrict myself to the`particular form of construction illustrated and described, but desireto avail myself of all modiiications which may fall within the scope ofthe appended claims.

Having thus described my invention, what I claim and desire to secure byLetters Patent is:

l. Avariable delivery pump for the hydraulic operation of presses andthe like including a plunger of constant, uniform stroke and a pressurefeed line leading therefrom and provided with abranch conduit, aconstantly rotated shaft having operative connection with said plungerfor actuating the same, a cam constantly rotating with said shaft `andpresenting a variablel cam surface,`valves effective in the .intake offluid to said pump and its discharge into said feed line, means engagingcertain of said valves for render ing the same ineffective during aportion of the puinp operation, a take-ofi in adjustable engage mentwith the variable surface of said cam, controlling the duration ofeffectiveness of said valve engaging means, and including relatively movable parts shiftable to adjust the take-od rela tive to the cam, and aplunger actuated by pressure trom said branch conduit for shifting cerofsaid parts of the take-nii relative to the other and to said cam.

2. A. variable delivery pump having an intake valve and an outlet valve,and a pressure line controlled by the outlet valve and having a branchconduit leading therefrom, a plunger having a constant stroke therein, aconstantly rotating shaft having means actuating said plunger, a cammounted on, and rotating constantly with, said `shaft and presenting avariablecam surface, a rocker arm having a free end engaging the intakevalve and movable to hold the said valve from seating during a selectedperiod of operation of `the pump, a rock. shaft in sections one of whichis axially movable and adjustably in engagement `with a branch conduit,a constantly rotated shaft having operative connection with said plungerfor actuating the same, a cam on said shaft and constantly rotatingtherewith and having two planes and a snail-shaped drop-off from oneplane to the other, a valve to bleed pressure from justing the take-01Tin respect to the cam to control the drop-off thereof from one cam planeto the other and thus vary the duration of opening of the bleed valve inproportion to pressure in the pressure line.

JAMES MAYNARD.

